Honing or the like machine



1949- F. w. WHITEHEAD EI'AL 2,461,943

HONING OR THE LIKE MACHINE Filed Sept. 25, 1945 e Sheets-Sheet 1 Feb; 91949. F. w. WHITEHEAD ETAL 2,461,943

HONINQ' OR THE LiKE MACHINE 6 Sheets-Sheet 2 Filed Sept. 25, 1945 9- F.w. WHITEHEAD ETAL YHONING OR THE LIKE MACHINE e Sheet s-Sheet 5 FiledSept. 25, 1945 1949. F. w. WHlTEHEAD E-TAL 7 2,461,948

. HONING OR THE LIKE MACHINE Filed Sept. 25, 1945 6 Sheets-Sheet 4jnvnd'lr' w FWmZ-zzzmz 2 W61 i overi y I J zmqbml "Feb- 1949- F. w.WHITEHEAD EI'AL 2461,94?

HONING OR THE LIKE MACHINE Filed Sept. 25, 1945 6 Shets-Sheet 5 v f 61Mr,"

Feb. 15, 1949.

F. W. WHITEHEAD ET AL HONING OR THE LIKE MACHINE Filed Sept. 25, 1945 6Sheets-Sheet 6 jwmzzzgmd M 6r. Zavar Patented Feb. 15, 1949 HONING ORTHE LIKE MACHINE Frederick William Whitehead and William GeorgeLovering, Bristol, England, assignors to The Bristol Aeroplane CompanyLimited, Bristol,

England, a British company Application September 25, 1945, Serial No.618,482 In Great Britain October 9, 1944 4 Claims.

This invention concerns improvements in or relating to honing or thelike machines.

Honing machines as at present used are adapted for abrading regularsurfaces such as cylinders and planes, the arrangement being that anarea of the surface of the abrading element engages with the part to bemachined throughout the honing operation this being permissible becauseof the regular nature of the surface of said parts. The presentinvention has for its principal object to provide a machine which isadapted for honing workpieces which do not possess such a regularsurface and in Which therefore it is impossible for an area of theabrading element to be brought into engagement with the surface of theworkpiece throughout the honing or like operation.

According to the present invention a method of performing a honing orlike operation is characterised in that the workpiece over Whose surfacethe abrading element is adapted to move constitutes a pattern for saidelement, the latter being freely mounted with respect to the workpieceto enable it to follow the contour thereof as it is moved over thesurface of the workpiece. According to another aspect of the presentinvention a machine for performing honing or the like operations ischaracterised in that the abrading element is adapted to make linecontact with the workpiece and is mounted to enable it to conform tovariations in the contour of the workpiece and maintain said linecontact.

The abrading element is preferably mounted for movement by the workpiecein a directiontowards and away from the surface of the workpiece whichis to be abraded.

In this way it is ensured that whilst the abrading element and theworkpiece are relatively moved so that the former travels over the,

surface of the lattenthe abrading element will accommodate itself tovariations in the contour of said surface.

If desired the abrading element maybe V workpiece.

A specific embodiment of .the present invention will now be described,by way of example, as applied to a machine for honing turbine mounted soas to be capable of tilting towards blades, with reference to theaccompanying drawings whereof' Figure 1 is a front elevation of theturbine blade which is required to be honed;

Figure 2 is a plan view thereof to an enlarged scale showing the outlineof the blade at various stations along the length thereof;

Figure 3 is a side elevation of a machine for honing turbine blades inaccordance with the present invention; 1 p

Figure 4 is a View in the direction of the arrow 4 of Figure 3 showing apart of the machine to an enlarged scale; 1

Figure 5 is a section on the line 5 5 of Figure 4;

Figure 6 is a view in the direction of arrow 6 of Figure 4;

Figure '7 is a section on the line 'l--1 of Figure 4; i v v Figure 8'isa front elevation of the turbine blade during the honing operation andshowing the hones in engagement with said blade, and

Figures 9, l0 and 11 are respectively sections on the lines 9-9, |9-llland I l-ll of Figure 8.

In order that the description of the construction and operation of themachine maybe clear-' 1y understood the form of the turbine blade whichis to be honed will first be described.

Referring to Figure 1 the blade comprises a shank 20 by which it isadapted to be secured to the rotor of the turbine and a vane 2| formedintegral therewith. The surfaces of the vane are to be producedaccurately with a fine finish by removal of a thin layer of material.The prehoned vane must therefore, be accurately formed and be slightlygreater in size than the honed article. The accurately produced blank tobe honed maybe produced by machining, grinding, precision forging orprecision castingthe vane blank is produced by the latter process. Thejprojected width or of the blade is constant throughout its length as isshown in Figure 2 so that the long axis b, of the vane lies midwaybetween the leading and trailing edges vof the vane. One-side of thevane is formed. with a concave surface throughout its length whilst thesurface on the other sideof the vane is convex. The curvature of theconcave, and convex surfaces at anyista tion on the long axis (i.e., onplanes passing through the long. axis b of the vane at right anglesthereto) is not constant as it is not a surface of revolution. Thus, ateachone of the stations 0, d, e, f and g the curvature constantly variesacross the blade as shown in Figure 2. At each of the stations reangleto the long axis b of the vane.

. 3 ferred to the outline of the vane is respectively indicated at d 6 fand The profile of the concave and convex surfaces varies from the rootof the vane to the tip thereof. The vane 2! is twisted around thelongitudinal axis 17 thereoffrom .the motto the-tip-so that a linejoiningthe-entry and exit edges of the' vane at a station near the rootis inclined with respect to another similarly disposed line at anotherstation along the vane. For example, .at..sta tion g a line joining theentry and exit edges of the vane is indicated at h and this line is:inclined with respect to the line i' joining the entry and exit edges ofthe Vane at-the station-c. "The concave and convex surfaces extendlinearly along the vane so that parallel;or:--substantially parallelstraight lines he on said surfaces. These straight lines (which arehereinafter referred to for convenience as coincident lines) are eachdisposed at the same or substantially the same One such coincident lineis indicatedin' Figure lxat jand -it--will be appreciated that the othercoincident lines on the concave and convex surfaces of the vane aredisposed "parallel or substantially "par- -allel=with the line shown.The vane-Tthickness at the root of the-bladeis greater than at'the tip-so that the linear'extensions of the curved 'surfaces-taper towards thetip :of the vane. This is shown in Figure 2 where the vane'thickness atstation-c is indicated-at ic whilst the vane-thickness-at station g isindicated at l.

The machine generally-:comprises a pedestal 22, a workhead 23 carried bythe :pedestal to receive the shank of the blade, a toolhead :24

'which'carries the -hones, and e'lectricmotor 25' for driving theworkhead and a gear box 26 through which the drive' from the electric."motor 25 is transmitted to the workhead 23. 'The "toolhead 24isdisposed immediately below the 'workhead 23 "so that when a blade isinserted in theworkheadthe vane thereof will project "through ,thetoolhead 24.

'The workhead comprises a spindle 2'l which is driven 'by'the gear-box26, -a, casing 28 into vwhich the lower endof the spindle 21 enters, a"bridgeepiece EBformedintegral with the casing 28,' pillars*'59 carriedby pedestal 22 and sup- Jporting"bridgepiece 58, and a jaw 29 carried bythepcasing 28 and adapted to receive the shank 20 of the turbine "blade.The shaft-21 vis rotated and reciprocated by means ofthe gear 21:02:26;the reciprocating movements of the shaft are imparted'to thebridge-piece 58 "(which slides on-pillars 59) and the casing '28.softhat jaw 29 and hence the 'turbineblade'is correspondingly moved.The rotary "moveiments of the shaft 21 are transmitted to an arm "30carried within casing28-for'which purpose .thelower. end of.the shaft2'! is supported ,in ltherasing 28. .The arm 39 carriesia ,pin 1'3! 50.ithat.1rotatlng of the shaftzl results in the in 'l3l ib'eincorrespondingly rotated. ."Thej pini 3| .enters ,a'fblockj'32 which ;is'mounted within'a ,,groove-' 33 so .as to be capable of .s'liding-move-,ment ltherealong;v theitgroove ;33 being formed ,in

a link 34 which is.pivotally mounted, bymeans ofithe bolt';35, tothepcasing' 28. Since the pin 3| .isat a smaller radial distance fromthe axis 4 jaw 29. The oscillations imparted to the link 34 aretherefore transmitted through the sliding block 36 in the groove 31 tothe member 38 and thus to the jaw 29 so that the latter is oscillated.The centre about which the oscillations referred .to take place,is.-arbitrarily selected to .lie ontheconcave side :of the vane andparallel with the long axis 2) thereof when the blade is mounted in thejaw 29-the arbitrarily selected l .centraofoscillation is indicated at min Figures 2 and 4. The centre of oscillation m is such thatthe vane Zlmoves over an arc of a circle which-approximates generally to thecurvature ofthe "concave and convex surfaces of the vane. 'Themembersofthe jaw 29 are adjustable towards and away from each other and are capa-"ble of being locked in position by means of the screw.39.

'The' toolhead 24 is provided with a plurality of hones three of whichengage the concave side of'the vane. 'The hones are .pressed .intoengagement with the vane whilst it is.;simu1- -taneously reciprocatedand oscillatedaszwill be hereinafter described so that-'the whole:ofgithc as t-wo surfaces of the vane are-brought undenthe "hones.

'The toolheadfilcomprises: a plurality of superposed units-40 each ofwhich is formed with a base plate 4| and a pair of stirrup members."{so-"spaced apart and secured to said 'base plate.

Each stirrup member is provided with a projecting flange 43 (Figure '7)whilst the basewplate has 'a central aperture '63 which is adapted toreceive 'the projecting flanges 13 of the next sfiadjacent toolhead unit40 when these are .dis-

"posed in superposed relationship as shown in Figure 4. 'lt'willbe=cleartherefore thatunitsflfl -of the toolhead'24 are located relativeto each -otherby'a-spigot joint. In the particular toolid-head I shown'in the accompanying drawings *threesuch superposed-units 40 are'spigoted together as described. The hones 44 are carried by radial-arms45 which lie between the'stirrup --members 42 and extend to'within thecentral aperture 'ofthe base'plate,=-each hone 44 being carried by onesuch arm '45. Oneof the stirrup "members 42 (see Figure '7) of eachtoolhead unit 40 is provided with-a pair of projectinglugs "-lfi'whichextend towards diametrically opposite 5 points of the unit, one such lugbeing'provided "for each arm 45. The threearms carrying the 'xhonesr44associated with the concave surface of the vane 2| are each pivotallymounted to one=ofxthe lugs '46 disposed one one side of the-:toolhead'whilst.the;arms-carrying the hones 44 :associatedwith' theconvex-surface of the vane are each pivotallymounted .to'one of the lugs46 ;disposed onthe opposite side of the toolhead. The pivotal, axis 11of' eacharm 45 is such that its hone 44 .is capableof movement towards 1and awayzfrom :the turhineblade when the latter nis mounted. .in thejaw. 29. When .-the-.-'b.lade is so mounted the pivotal axis nisjdisnosedparal- .lel with thelong axisbpf the:,:blade.

.Tlie form 10f; the. surface..-of the vane. 2 l .pro- ..hibits.th.e useof .ashone vwhich engages ovecan -..-area .with .the .sur;face.-of :thevane. I Accordingly resortiis hadto ahonehaving aponvexsurface whichextends along .that edge thereof that -is 7 adapted tomengagewiththesurface of the. vane so that at all positions ofengagementthecrest of the. hon,e. makes .a line. contact with.saidsurgfacelisee Figures 8 to 11). LIn yiewwofthegfact 'that'thecoincident lines von he, concave and convex surfaces of the vane aredisposed at an that the crest of each hone lies upon a coincident lineof the vane. The hones associated with the convex side of the vane aresimilarly disposed. In this way it is ensured that the line of contactbetween each hone 44 of the surfaces of the vane 2| will be maintainedthroughout the honing operation. Furthermore, the pivot point n of eacharm 45 associated with the concave surface of the vane iscircumferentially spaced from the next adjacent arm so that the crestsof the three hones are upon the same coincident line as is clear fromFigure 8. This arrangement of the lugs 46 and the arms 45 is shown inFigures 6 and 7.

A similar construction is provided for the arms 45 associated with theconcave surface of the vane.

To provide for the variation in the vane thickness which existsfrom theroot thereof towards the tip, each of the pivotal arms 45 is formed intwo parts. As shown in Figure 7 each arm 45 comprises an upper-arm 4'lwhich is pivotally mounted to one of the lugs 46 carried by the stirrupmember 42 and a fore-arm 48 pivotally mounted to said upper arm 41. Tothis end, the

fore-arm 48 is provided with a pin 49 which extends longitudinallythrough the upper-arm 47 and is free to rotate therein, the axis ofrotation of the fore-arm being normal to the pivotal axis 12 of the.upper-arm. The fore-arm 48 carries the hone 44.

The construction of each arm 45 is such that the pivotal axis of thefore-arm 48. (that is the pivotal axis of the pin 49) intersects thepivotal axis 71 of the upper-arm 41 and is tangential to the crest ofits associated hone 44.

Associated with each arm 45 is a pair of cylinders 50, the plungers 52of which engage the upper-arm 47. The cylinders 50, 5| are formed in thestirrup members 42 and each of the pair of cylinders is disposed onopposite sides of the arm so that when cylinder 5| is brought intooperation the arm 45 is turned about pivot point n to move theassociated hone 44 towards and into contact with the blade so thathoning may proceed and when the cylinder is brought intoop'eration thearm 45 is turned about axis n to carry the associated hone 44 away fromand free of the blade. The cylinders-5| will be referred to as thehoning cylinders and the cylinders as the return cylinders. The honingand return cylinders 5! and 513 respectively are connected with a supplyof air under pressure by means of pipe lines 6| and 60. All the pipelines 6| of the honing cylinders 5| of the toolhead 24 are connectedtogether to a common pipe line 53 (Figure 3) so that air issimultaneously applied thereto. Similarly all the pipe lines of thereturn cylinders 50 are connected together to a pipe line 54 so that airwill also be simultaneously applied to them. Disposed between the mainpipe line 55 which carries the compressed air to the tool-head and eachof the branch pipe lines 53, 54, is a valve 56, 51. It will beunderstood of course that suitable means are provided for exhausting thecompressed air from the set of honing cylinders 5| when pressure air ispassed to the set of return cylinders 50 and vice versa.

The operation of the machine is as follows:

Let it be assumed that the valve 51 is adjusted to permit air underpressure to pass by pipe lines 54 and 66 to all the return cylinders 50'of the toolhead that the honing cylinders 5| are connected to exhaust,the valve 56 being closed to cut off the supply of compressed air fromsaid honing cylinders. The set of hones 44 associated with the concaveand convex surfaces of the vane are therefore moved away from eachother, the arms 45 pivoting on lugs 46. The turbine blade is mounted inthe workhead so that the shank 20 thereof is gripped in the jaw 29 andso that the vane 2| is directed towards the toolhead. During thisoperation the workhead is disposed sufficiently far above the toolheadto permit the insertion of the blade: The bridge-piece 58 is thenlowered to bring the workhead to the position shown in Figure 4 and sothat the vane 2| of the turbine blade enters the toolhead 24'andlies'between the two sets of hones 44. When the machine is set up asdescribed, valve 51 is closed to cut off the supply of compressed air tothe return cylinders and thereafter valve 56 is opened to connect thehoning cylinders 5| with the compressed air supply. As a result thereturn cylinders are connected to the exhaust and the arms 45 are movedby the honing cylinders so that the hones 44 are simultaneously broughtinto contact with the two surfaces of the vane. The motor 25 is thenstarted and transmits drive as described through the gear-box 26 to theworkhead 23 so that the turbine blade has imparted to it a compoundmovement of reciprocation and oscillation. The honing operation thencom.- mences and continues whilst the compressed air is admitted to thehoning cylinders 5|. It will be clear from what has been stated abovethat the two surfaces of the vane are each engaged by three hones 44each of which is movable independently and applied to the surface of thevane by an associated individual cylinder 5|. It is essential if theabrading operation is to take place uniformly over the surface of theblade that each hone be applied with the same pressure and that thelatter does not vary substantially throughout the honing operation. Tothis end the air supply for all the honing cylinders is obtained from acommon source by way of the main pipe line 55 and a relief valve 62 isprovided in said pipe line to insure that the air supply is maintainedat substantially constant pressure. v

Throughout the operation the hones associated with the concave surfaceare in contact with the latter so that the line of contact between eachhone and the concave surface is disposed upon a coincident line asdescribed above. A similar disposition of the hones relative to theconvex surface is provided for. During the honing opera-- tion theoscillating movement imparted totl'ie blade brings the whole profile ofthe vane at each station along its length beneath .a hone. The lattermust therefore be capable of adjustment to accommodate for thevariations in the radial distances from the axis of oscillation m topoints on the profile of the vane. This is provided for by the pivotalmovement which the hone carrying the arms 45 enjoy relatively to thelugs 46 of the stirrup member 42. Since the part of the vane along thelength thereof which is brought beneath each hone is continuouslychanging due to the reciprocating movement imparted to the blade and inview of the fact that the vane suraracesxtaper from- -cthearootivtor-the: tip, mire-radial distance from the axis-.ot-roscillation-torcorresponding points :onthe surface of" the rblade atz'difierentestations will vary. 1By corresponding .:points is meantpoints at different :stations which (lien-upon thelsame coincident:line. The James 44 arecapable of adjustment =to accommo.kiatenforthis-profile variationtby the pivotal moveorient-which thehoneacarryingforearms-48 enjoy :relatively' to the upper-arms 41.

=Itwill be seen therefore that by mountingeach r-hone-so that-it:is:free=-to :move-about two axes will -will accommodate'itself tothe contourw-hich vis :brought-rbeneath it during the reciprocatingandwoscillating movement of the vane and that 'the line contactestablished between each home 44 :and the vane 2] along a coincidentline "is ,maintained throughout the honing operation. :It -isonly1necessary therefore to select the reciprowriting: and oscillatingmotions so :as to ensure that: thechones associated with each-. surfaceof thevane (concave or convex) :Wlll pass entirely over thevanein*acyclic manner. Thesamount oft-material"=removed-twill-lthen be uniformover the-surface of the blade.

.llta'is :torbe understood that the turbine blade .;constitutes'apatternrwhich is -followed-r by the .-hones 44 during! themachining-operation and --:that the form of the prel-machined blade:deter- --mines-theshape loftthe'blade whenitis machined. It:isaessential therefore'that the pre-honed blades be*accurately;produced dimensionally and :geo-

:metricallyrsothat they areisimilarto the'finished rblade. This :maybe-done zeither .by forging or casting. Accordingly :a honing machine inacoordance withr-the present invention finds .a par- .ticularapplication whenused for producing a highly "polished surfaceon turbineblades which rare'required to :-beaccuratelyproduced within smalldimensional limits.

The construction of the toolheaddescribed aboveis such that-thehoningmachinelis readily adapted .for machining articles -of differentlengths since in order to accommodate forv variationslin 'thelength ofthe :article it is only necessary -to provide :the v required number ofsuperposed-toolheadtunits. For instance, if a machine be :adapted tohone a turbine blade which is Ttwice thelength of thebladeiforwhichflthree ltoolheadunits havebeeniprovided, thenit is onlynecessary to incorporate a further three such toolheadiunits..Therspigot, joint betweenrthe various units readily enables this to bedone.

Although the specific embodiment of the .in- \vention .has been.vdescribed as appliedto .a machine. forhoningiturbineblades itis to beunderstoodthat it thasapplication to the honing .of

.l other articles. -.Moreover,. the machine :is capable ,of adaptation.forihoning-iplane. surfaces as well .-as curvedflsurfaces.

lnsuchlavcase it willbe clear I "that .thelarticle-willbereciprocated intwo dir'ec- .tions'-.instea'd.of havin'gllimparted to it a reciproscatin'g andloscillatingmovement.

' Weclaim: p

' l. A honing ..or .the like ::machine for cblades having xacurvedsurface uponrwhich lieicoincident lines as hereinbefore definedcomprising-a carrier forthe blade, means tovoscillate the.car-

rier about anaaxis approximating to the' centre ofcurvature of theblade, an abrading:-e1ement to engage the blade along a coincident lineonly,

:a first and second support-for the abradingele- .ment whereby thelatter is pivotally mounted for "movement towards land away'from the,blade about. an axisparrallel with the axis of oscillation of the bladeand about an axis normalto said pivotal axis for-:tilting movements.relatively .toa coincident line on the blade and'meansfor resilientlyholding the abrading element against the blade so that it-isindependently movable about each supportsolelyby the oscillatingbladewhich determines its rownfinalshape,

2. A rhoning machine for blades having :a curvedsurface upon whichliecoincidentrlines as hereinbefore :defined comprising alcarrier forthe blade-meansto oscillate thencarrier about an .axis approximating.tov the zcentrelofacurvw ture .of the blade,. a plurality ofiabradingfele ments in superposed relationship each to engage the blade.along .a coincidentline .only,-.,a. flrst an'd second support foreachiabrading elementwhereby the element is pivotally mounted iiorrmove-.ment towards and away Iromthe b1ade...about an axis parallel with theaxisuof oscillation of the blade and about anaxis normal to.saidtpivota-lvaxis rfor tilting movements relative .tota

coincident line. on theblade and means..for...re-

"the abrading elements are applied to .a work- ,piece by .means of.pneumatic pressure.

4.-A1 honing machine as claimed in claim2 wherein the blade carrier ,isreciprocated along the axis of oscillation thereof whilst it is beingoscillated.

' FREDERICK WILLIAM WHITEHEA'D.

WILLIAM GEORGE. LOVERING.

REFERENCES CITED The following references are of 'record inrthe file ofthis patent:

UNITED STATES .PATENTS Number Name Date 1,-515,;568 Fleming=etal, Nov.11,:1924 1,536,928 Reitz etal May 5, 1925 '-1, 684,8'72 Logue-i-Sept.*18,.-1'928 -1,84 3,301 Player: et=al.. -'Feb. 2,:-I932$2,164,867

